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HN50

Modding my ST102

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A few months back I asked about whether it was better to paint or flock the inside of my telescope, with the response being that flock is better.  I bought the flock in January and after seemingly interminable DIY weekends, I have finally been able to sit down and do it, along with some other work.  This thread is how it went - it does not cover anything that has not been covered before but I figured I would post it anyway.

 

I had been thinking about upgrading the focuser but decided to try and lubricate the existing one first.  I took the focuser apart and came face to face with the so-called Synta glue I had heard about.  It had the same consistency as half set epoxy resin(!).

image.jpeg

So I took it all apart, cleaned the parts up and relubricated with some Shimano bike grease I had used on my AZ4 mount.  It is smoother, I was not expecting it to turn into a better focuser but I thought I would give it a try before shelling out for a replacement.  

 

Next though was the flocking.  I cut it into 5cm strips and worked my way round the insides.  Before:

image.jpeg

And almost finished:

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As suggested, I gently brushed to remove loose fibres and then lightly sprayed with hairspray.

 

And after I had given myself a new barnet I thought I had better get back to working on the telescope.  Bahaha.

 

Anyway, it seems to have helped cut down stray light.  I also flocked the inside of the focuser draw tube - taken half way through so I could convince myself I could see a difference:

image.jpeg

And also the inside of the dew shield:

image.jpeg

I did have quite a job trying to get the white lens cell off.  I assume that it will screw off but the black gunk holding it in place would not budge.  So, not wanting to force anything, I decided - gulp - to unscrew the lens cell itself to gain access that way.  I held the lenses in a micropore cloth and made a note of how they sat together and which way they sit in the cell itself.

 

I was a bit nervous about this as I was sure I read somewhere that the elements are aligned when assembled.  I tried to keep them together as precaution but if they have become misaligned I can give myself another project to realign them(!). 

 

I did take the opportunity to blacken their edges with a permanent marker.  I saw this on a YouTube video for the ST80 and decided as everything was in pieces I might as well have a go.  It has nicely darkened the edges - the photo below is half way through to give an idea of the difference.

image.jpeg

 

Anyway, I was able to reassemble it all successfully and set it up to see that nothing has broken.  Checking the view, distant trees seem okay but the acid test will be under the stars.  All in all though I am quite pleased with the work and am looking forward to a clear night.  

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Did the re-greasing make any change to the focuser?

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8 hours ago, ringz said:

Did the re-greasing make any change to the focuser?

Hi,

It does feel a bit smoother, yes.  I would not say it has turned into a silky smooth action but I guess if I want that I have to pay for an upgrade.  

I also tightened the grub screws on the upper side of the focuser maybe an eighth of a turn.  The draw tube had previously rocked slightly when pressed and now it doesn't.  

Anyway the action of the focuser feels a bit more direct now.  Hope that helps.

Dave

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Nice write-up! Some bicycle-grease can do a world of good! But I've taken it a notch up and replaced the focuser altogether, on my AR5 127mm F/9.3 refractor. Something tells me many folks should stick with the grease. Why? My reason is a smidge over halfway-down the page here:

https://stargazerslounge.com/topic/266931-meade-infinity-102/?page=14

They can really mash the back-end onto refractors in Synta-Land. The GSO Crayford is great. The Antares adapter works as it should. But getting the whole she-bang together can be a bear!

As for bicycle-grease, I'm a bicycle-mechanic in another of my worlds. I've often encountered grease more than 20 years old - still doing their job without a hitch. And this is on things that get a heck of a lot of high-pressure application - like in the bottom-bracket (where the pedals/cranks go through) of a cycle. So your focuser should be good-to-go for a long time.

Enjoy & thanks for posting!

Dave

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Hi Dave,

Thank you for the post.  I read the link and I think that having to remove the focuser as you described  might be a bit out of my comfort zone. :)

I am planning to stick with the r&p for the time being before I decide on an upgrade.  Plus the grease I used is fluorescent yellow which I rather like.

Otherwise I might keep my eyes open for some of the larger metal knobs that they have on the st120/st150 for slightly finer control as when I have gloves on I do find the plastic ones a little slippy.  I think I have seen mention of using a clothes peg which is another option.

Cheers,

Dave

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There are many who think well of the lids off peanut-butter jars - with a hole made in the middle - and similar goods to make the best 'fine-tuning' on telescope-focusers. Ever watch a record (I know this dates me) spinning on a turntable? It appears that the center of the record is going much faster than the outer edge. This odd optical illusion actually works in practice! Make a bigger wheel.

Have fun -

Dave

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On 15 May 2016 at 12:13, Dave In Vermont said:

There are many who think well of the lids off peanut-butter jars - with a hole made in the middle - and similar goods to make the best 'fine-tuning' on telescope-focusers. Ever watch a record (I know this dates me) spinning on a turntable? It appears that the center of the record is going much faster than the outer edge. This odd optical illusion actually works in practice! Make a bigger wheel.

Have fun -

Dave

Hi Dave,

I had never thought of that, I rather like the idea.  It would even have a knurled edge. :)

Thanks again,

Dave

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i did that with my celestron 130 - replaced the grease with the last smidges of some molybdenum carbide grease i had left over and made a 3:1 focuser by gluing a jam lid on to one of the focus knobs. made it easier to grip by stretching a rubber band over the rim of the lid and putting a couple of spots of superglue on to stop it sliding off.

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Nice job! I recently flocked my Travelscope 70 which I have been using as a guide scope. The 5cm strips seems a much better idea than a full circumference like I did! I also flocked the knife edge baffles with rings of flocking material. Don't know if it will improve things but thought, 'hey, whilst I'm in here...'.

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On 16 May 2016 at 19:29, nicks90 said:

i did that with my celestron 130 - replaced the grease with the last smidges of some molybdenum carbide grease i had left over and made a 3:1 focuser by gluing a jam lid on to one of the focus knobs. made it easier to grip by stretching a rubber band over the rim of the lid and putting a couple of spots of superglue on to stop it sliding off.

Hi,

Apologies for the delay in replying.  Thanks for the post, that gives me something to think about when I modify my focuser.

dave

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On 16 May 2016 at 21:16, southerndiver357 said:

Nice job! I recently flocked my Travelscope 70 which I have been using as a guide scope. The 5cm strips seems a much better idea than a full circumference like I did! I also flocked the knife edge baffles with rings of flocking material. Don't know if it will improve things but thought, 'hey, whilst I'm in here...'.

Hi,

Apologies for the delay in replying.

Thank you for the post.  I could not decide what to do about the baffles myself.  I didnt in the end as I was a bit concerned about fibre shedding and wanted to avoid too many cut edges, and to be honest I found it fiddly enough with rectangular strips(!).  Did you do them in one piece as well?

Dave

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No problem Dave, some people do have lives outside of SL! :icon_biggrin:

I did each side of the baffle with a ring of flocking on each side. I must admit it was a bit fiddly getting the ring to sit squarely(!) on the baffle, but there in now. One thing to be careful about if anyone else is going to try it is that the baffles in the Travelscope 70 don't appear to be fixed in position. They are in with just a 'resistance fit' on a few lugs bent out from the ring itself. I found this out after I had moved the main tube baffle whilst trying to get the flocking material to stick!

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